This invention relates to plug and receptacle connections for joining two fiber optic cables together for optical energy transmission from one cable to the other. More particularly, it relates to the provision of an optical fiber connector that includes a tubular ferrule for receiving a bared end portion of an optical fiber and to a construction. of the connector that allows for an adjustment of the angular position of the optical fiber by rotating the ferrule and an end portion of a fiber optic cable that extends into the connector until a desired rotational alignment of the optical fiber is achieved, at which time the end portion of the fiber optics cable is fixed in position relative to the connector so that the rotational alignment of the optical fiber is maintained.
FIG. 1 of my allowed, pending U.S. application Ser. No. 09/649,283, filed Aug. 28, 2000, and entitled Plug And Receptacle Connection For Optical Fiber Cables With Alignment Feature, presents one example of a plug and receptacle connection for an optical fiber cable. application Ser. No. 09/649,283 sets forth a detailed description of the need for rotational alignment of the two optical fibers that are to be joined in order to obtain optimum results in the transmission of optical energy from one optical cable to the other optical cable. application Ser. No. 09/649,283 discusses prior art alignment systems that allow for a set number of azimuthal positions of the two cables. application Ser. No. 09/649,283 also discloses an alignment system in which an infinite number of azimuthal positions can be obtained. The present invention provides another way of adjustably positioning an end portion of a fiber optic cable and its optical fiber in an infinite number of azimuthal positions, for achieving optimum optical energy transmission from a first cable to a second cable.
The optical fiber connector of the present invention is basically characterized by a tubular outer housing and a tubular inner housing within the outer housing. The tubular inner housing comprises a forwardly opening front socket and a rearwardly opening rear socket that is in axial alignment with the front socket. A rear portion of a tubular ferrule is received within the front socket of the inner housing. The tubular ferrule has a center opening that is sized to receive a bared optical fiber. The tubular ferrule also has a front portion that extends forwardly from the rear portion of the ferrule and the front socket. A key ring is provided in the outer housing surrounding the front socket of the inner housing. The key ring is held against rotation relative to the outer housing and it includes a cylindrical inner surface. The front socket has a cylindrical outer surface that is sized to receive the cylindrical inner surface of the key ring. The cylindrical surfaces are sized such that the cylindrical inner surface of the key ring frictionally engages the cylindrical outer surface on the front socket. The inner housing and the ferrule are rotatable in position relative to the outer housing and the key ring when a rotational force is applied to them that is sufficient to overcome the friction between the cylindrical inner surface of the key ring and the cylindrical outer surface on the front socket.
In preferred form, the key ring periphery includes alternating projections and cavities and the tubular outer housing includes complementary projections and cavities. The projections on the key ring are received in the cavities in the outer housing and the projections on the outer housing are received in the cavities in the key ring. The projections and cavities lock the key ring to the outer housing and prevent the key ring from rotating relative to the outer housing.
Preferably, the tubular inner housing has a radially outwardly directed flange at its front end that is positioned to block forward movement of the key ring along the cylindrical outer surface of the front socket of the inner housing. Preferably also, the inner housing has a radially outwardly projecting girth ridge on it that is spaced axially rearwardly from the flange. The flange, the ridge and the cylindrical outer surface together define a girth groove surrounding the inner housing in which a base portion of the key ring is received. The ridge blocks rearward movement of the key ring along the cylindrical outer surface on the front socket of the inner housing.
In preferred form, the tubular inner housing comprises a forwardly facing tool receiving portion that is radially outwardly of the front socket. The tool receiving portion is sized and shaped for receiving a complementary end portion of a tool that is used for rotating the tubular inner housing and the tubular ferrule relative to the outer housing. The tool receiving portion may comprise at least one forwardly directed tool-tip receiving opening in the forward end of the tubular inner housing. Preferably, however, the tool engaging portion comprises at least two forwardly directed tool-tip receiving openings in the forward end portion of the tubular housing. These openings are circumferentially spaced apart and are radially outwardly from the front socket. Preferably, there are two tool-tip receiving openings that are spaced substantially one hundred and eighty degrees (180xc2x0) apart.
In the preferred embodiment, the outer housing includes a front section and a rear section and the two sections are telescopically connected together. The front section of the outer housing has a rearwardly directed socket and the rear section of the outer housing has a forwardly directed tubular pin that fits into the rearwardly directed socket in the front section of the outer housing. A lock structure is provided for connecting the front section of the outer housing to the rear section of the outer housing. This lock structure may comprise of at least one opening in a side wall of one of the housing sections and a complementary projection on the other housing section. By way of an example, the front section of the outer housing may include side wall openings on opposite sides of the front section. The rear section of the outer housing may include projections sized and positioned to snap fit into the openings in the front section when the rear section is telescopically moved into the front section.
Preferably, the rear section of the outer housing includes a central opening in which a rear portion of the inner housing is received. The inner housing includes a radial shoulder, intermediate its ends. The rear section of the outer housing includes a radial shoulder intermediate its ends that is spaced rearwardly from the radial shoulder on the inner housing. A coil spring is positioned within the rear section of the outer housing in a position surrounding a middle portion of the inner housing. The spring has a first end that abuts against the radial shoulder on the inner housing and a second end that abuts against the radial shoulder on the rear section of the outer housing. This spring biases the inner housing, the lock ring and the ferrule axially forwardly within the outer housing.
The front section of the outer housing may include a radially inwardly directed flange that is forwardly contiguous the radially outwardly directed flange at the front end of the inner housing. The coil spring biases the flange on the inner housing forwardly against the flange on the outer housing.
Other objects, advantages and features of the invention will become apparent from the description of the best mode that is set forth below, form the drawings, from the claims and from the principals that are embodied in the specific structures that are illustrated and described.